The present invention relates to a mirror electron projection (MPJ) type (secondary electron projection (SEPJ) type included) or multi-beam scanning type electron beam apparatus, which irradiates an inspection target with a planar electron beam to detect mirror electrons, and to a method and apparatus for inspecting pattern defects with the electron beam apparatus.
A mirror electron projection type semiconductor wafer scanning electron beam apparatus, which emits a planar electron beam for throughput enhancement, is disclosed, as a replacement for a scanning type that emits a point electron beam, by Japanese Patent Laid-Open No. 202217/2003, “Hasegawa et al., Development of EB wafer inspection technique by using mirror electron projection, LSI Testing Symposium, 2004,” “Murakami et al., Development of an electron beam inspection system based on projection imaging microscopy, LSI Testing Symposium, pp. 85-87, 2004,” “Nagahama et al., Inspection performances of the electron beam inspection system based on projection electron microscopy, pp. 921-928, SPIE Vol. 5375, 2004,” “Satake et al., Electron beam inspection system for semiconductor wafer based on projection electron microscopy, pp. 1125-1134, SPIE Vol. 5375, 2004,” and Japanese Patent Laid-Open No. 363085/2004.
Japanese Patent Laid-Open No. 202217/2003 describes a defect inspection apparatus that forms an electric field on the surface of an inspection target for electron beam speed reduction purposes, causes a planar electron beam having a predetermined area, which includes an energy component that cannot reach the surface of the inspection target due to the speed reduction electric field, to reflect from a place close to the surface of the inspection target, uses an image formation lens to form an image, acquires the images of a plurality of regions on the surface of the inspection target, stores the acquired images in an image storage section, and compares the stored images of the plurality of regions to check for and locate defects in the regions.
Japanese Patent Laid-Open No. 363085/2004 describes an inspection apparatus that includes electron irradiation means for generating electrons, forming an image at a predetermined magnification to produce a crossover, and irradiating a substrate by using a desired cross-section shape; means for relatively moving a charged particle irradiation region on the substrate by moving at least either electrons emitted to the substrate or a stage that retains the substrate; a detector for detecting electrons that have acquired the surface information about the substrate; means for acquiring a detected image of an inspection target die in accordance with the information about the substrate surface that is detected by the detector; means for acquiring a reference die image, which serves as a comparison standard for a detected image of the inspection target die; and comparison means for comparing the image of the inspection target die against the reference die image.